Arc quenching plates are used in conjunction with electrical contacts, for example in circuit breakers or, for example, in electromagnetically operated contactors. The arc quenching plates serve the purpose of leading an arc away from the contacts, where the arc is produced as the contacts open. Leading the arc away from the contacts facilitates extinguishing the arc. Arc quenching plates have in the past been mounted in a variety of methods, none of which lend themselves to easy assembly of the arc quenching plates in the body of an electromagnetic contactor or in a circuit breaker, so that the assembly can be automated. Automation may be, for example, by a robot assembly step. A further consideration in mounting an arc quenching system is to direct the exhaust of arc gases so as to minimize the danger of injury to a person who is working on the electrical system.
An example of arc quenching plates assembled into an electromagnetic contactor is shown in U.S. Pat. No. 4,446,347, issued to Eguchi, et al., on May 1, 1984. In the Eguchi reference the arc quenching plates are mounted in slots in a two part mounting block, and the parts of the mounting block are held together by bolts. Also arc gases are vented in a direction substantially parallel to a plane of the arc quenching plates.
Another example of mounting arc quenching plates in a frame and securing them by bolts is shown in U.S. Pat. No. 3,091,677, issued to Rosing on May 28, 1963.
In U.S. Pat. No. 3,448,231, issued to Heft, on June 3, 1969, there is shown a system for retaining arc quenching plates by inserting ears formed in the plates into retaining slots formed into mounting plates. The mounting plates are then placed into the structure by insertion into matching openings, and retained by a louvered structure bolted into place.
An example of arc quenching plates retained within slots formed in a two part housing which is assembled together by bolts, and which has angled slots in a front retaining member for venting of exhaust gases is shown in U.S. Pat. No. 3,515,829, issued to Hurtle, et al., on June 2, 1970. The arc gas venting channels of the Hurtle, et al. reference prevent insertion of the arc quenching plates from outside of an assembled housing.
Arc quenching plates mounted internally to a housing for an electric contact device are shown in U.S. Pat. No. 4,401,863, issued to Lemmer, et al., on Aug. 30, 1983. The mounting for the plates shown in the Lemmer reference does direct the arc gases to the side of the device, but the plates are not conveniently arranged for robot insertion within the apparatus.